The United States military is planning a new offensive later this year to drive the Taliban from the southern Afghanistan city of Kandahar.
A White House official said on Friday the current campaign against the Taliban in Marjah in the neighbouring Helmand province is a "prelude" to a bigger operation.
He described Marjah as "a tactical prelude to a comprehensive operation in Kandahar City."
An offensive by NATO forces in Marjah began in mid-February and has several more weeks to go.
The BBC reports that Kandahar, Afghanistan's second largest city, was once a Taliban stronghold. Suicide attacks are frequently carried out there.